The most common and most likely answer to this crossword clue is the 9 letter word PTEROSAUR
I've seen this crossword clue in Financial Times
P
T
E
R
O
S
A
U
R
More clues leading to the result PTEROSAUR
- Prehistoric beast – monster – spotted, in reports
- Ground or pasture for ancient beast
- Fear something with teeth, did you say? Old reptile
- Reptile‘s fear understood when picked up
- Old flier rose up acrobatically, with art
- Botched up art containing winged deity that once flew
- Platinum and gold surround love god. Right old flier.
- Expressed alarm saying this beast could fly
Buddy explains!

The straight part
We know that "Old reptile" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case old reptile = pterosaur.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does PTEROSAUR mean?
PTEROSAUR noun- Any of several flying reptiles, of the extinct order Pterosauria, including the pterodactyls.